System for treating petroleum oils



"July 2 1. 1931. c. wl. s'rRA'TFoRD 1,815,365

' SYSTEM FOR TREATING'k PETROLEUM OILS originan Filed Nov. ge, 1926 s sheets-shear 1 c: A c: c:

, L X X July 21. `1931. c. w.srR'ATFoRD' Y 1,815,356

SYSTEM FOR TREATING PETROLEUI OILS Original Filed Nov. 26, 1926 3 Sl'1ee'...-*-Sluaet.v 3

/7 ATTORNEY litatent'edfJuly 21,l 1931- PAT-ENT,.- or-'FICE wALooTT smnnrronn, or KANSAS CITY, mssoURr original ppuation mea :member 2s, 192s, serial No. 150,678. Divided a'na 'm114 application mea June 12, 1929. serial No. 370,172.

This invention relates to improvements in .fresh soda reservoirs, designated asl, 2, 3

a system of treating hydrocarbon distillates for the purpose ofremoving color-bearing, lre'sinous and unsaturated bodies', or other [5j hydrocarbon products.

This applicationis a division of m copending application Serial No. 150,678, filed November 26, 1926.

In the treatment of hydrocarbons to eliminate sulphur and other objectionable-compounds 'the oil is given a chemical treatment or treatment with an agent whichhas selective chemical ainity or physical solvent powers, or adsorptive characteristics with reference to the bodies to be removed. When oxygen or air is present during the chemical treatment, wasteful polymerization of otherwise`useful constituents occurs. The advantagesof the present system lie chiefly in the utilization of a small self-contained apparatus for a given capacity, hence low first cost and lthe employmentof contactors or mixers adapted to rapidly mix to a remarkable'degree ofintimacy the hydrocarbon and treating material. Furthermore, the system aii'ords an apparatus by means. of which the treating rates may be regulated andare adjustable as to contacttimer The separation after treatment is rapid and complete'and the hydrocarbon distillate is not in contact with the acid for a longer period than is necessary toeffect proper treatment or suliiciently long to cause objectionable polymerization.

- Fig. 1 is a iow diagram of the treating system.

Fig. 2 is an elevational detail, with parts in section, of the contaotor. and settler or separator.

Fig. 3 is a view taken along the line 3-3 inFig.2.

Fig. 4 is` an enlarged sectional view of the l cont-actor shown in Fig. 2. y

Fig. 5 is a view taken along the line 5- in Fig. 4.

Fig. 6 is a view.taken along the linel 6-6 in Fig. 4. Referring to the drawings and particularly 'to Fig. l, at the bottom of the sheet are shown fresh acid, spent acid, spent soda andV 'ignated as L01, L02-, L08 and L04.

and 4, respectively. Above the reservoirs or tanks are pumps for handling the acid, soda vand distillate; these pumps are designated as 'P1 to P7 inclusive. Pumps P1 and P2 distribute the fresh acid through the system. Pumps P6 and Pf distribute the soda solution. Pumps P3 and P., supply the hydrol carbon dustillate to the contactors. Pump P5 discharges spent acid or spent soda from the system to storage. Pump P5 may also be used for pumping out hydrocarbon distillate from the system or evacuating any stage of the system without disturbing the operation. About the respective pumps P1 to P7 is shown reverse iow manifolding for evacuating the system of the different liquids.

Above the set of pumps are iow control mechanism designated as F01, F02, F03 and F04. The particular details of the mechanism form no part of the present invention;

the interposition of the flow control mechai nism in the lines serving solely to malntain Y from the separate contactors are the settlers or separators, hereinafter more :fully described, and designated in the iow chart as S1, S2, S5 and S4. Each of the separators is equipped with level control mechanlsm dTelflsseparators mayeither be in the form of settlers or centrifuges.

To facilitate reading of the ow chart and to make the understanding of the system more comprehensive, certain of the lines have been designated and arrows placed upon the lines to show the direction of the flow of the liquid within the lines. 1

The system is lso connected that the hydro seda a-nd successive acid treats with a nal soda treat.

It is 'recognized that it is common practice to successively treat hydrocarbon' distillates in separate stages, but the rapidity and effectiveness of the present method of contacting, together with the complete and efficient separation after treatment of a large quantity of oil by means of the apparatus vhereinafter described, and the details of the mechanism used in the system provide the novelty of the present invention.

The hydrocarbon distillate to be treated is supplied by means of pumps F3 and P4, and is admitted to the initial contacter 5 by means of a pipe 6, as shown in Fig. 2. This contacter comprises a casing or shell, desig nated as 5a in Fig. 4, which is jacketed as shown at 7. The jacket surrounding the shell is spaced from the shell by means or a spiral spacer pipe 8 which directs the flow of water which is circulated through the jacket from the inlet line 9 te the discharge line 10. An important feature of the cooling water circulation is the fact that the coolest water is supplied to the jacket at a point substantially where the acid and oil first contact and mix and where the greatest heat will occur, as hereinafter pointed out. Positioned within the shell 5a is an open ended flow directing tube 1l supported by vertical support vanes 11a.

Mounted above the contacter 5 and bolted to the removable head 12 is a motor 13 supl ported upon a suitable standard. This motor is' directly connected through a shaft 14 to a shrouded propeller 15 positioned in the lower part of the flow tube 11. The lower extremity of the shaft 14: is held in place on a floating ball bearing 16. The blades of the propeller are so pitched as to cause a downward circulation of the oil through the flow tube, thus the oil, introduced through the inlet pipe 6 completely fills the contacter, is picked up by the propeller and is driven at high velocity through the flew tube.

The fresh treating agents are supplied by their respective pumps and introduced into the bottom of the contactors through a line designated as 17. In Fig. 2 of the drawings this line is connected to the settler or separater, but it is understood from the flow chart that the initial stage of treatment will receive its supply of treating agent'direct from the supply pump. The treating agent on entering the bottom of the contacter is picked up .by a centrifugal pump 18 which discharges it at high velocity through a plurality of I holes 19 shown in Figs. 4 and 6. These inlet holes are drilled through the bottom 20v of the contacter.

It will be noted also that this bottom is llighter because of centrifugal force.

lar space outside the flow tube.

comes through the How tube in order to direct the mixture in an upward direction in lthe annular space between the shell of the contacter and the outside of the flow tube.

In producing the flow of eil downwardly through the flow Atube the oil discharged from the blades of the propeller will have a high velocity in axis and seme rotation. This rotation oftotal liquid will cause the heavier liquids to partially separate from the This centrifugal force will project the heavier liquid through a series-of radialholes or vents 21 drilled in the flow tube, and thus form a screen across the up-flowing liquid rising in the annular space between the outside of the iiow tube and the shell of the contacter, again mixing with it. The high pressure at the discharge side of the propeller contributes to the formation of the screen by the projection of the liquids through the radial holes.

There is also a local cyclic movement around the shroud of the propeller and a zone of high turbulence existing between the moving rim of the propeller and the flow tube which are important factors in promoting the intimacy of mixture and dispersion attained. Below the cross feed discharge vents 21 or holes through which the liquids are projected, is an element 22 termed an unwinding` head. This head comprises a plurality of vanes positioned to reduce the rotation or spiral flew of the liquid produced by the propeller to a vertical How. The pitch of these blades or vanes is 'suihcient to redirect the flow so that the liquid is directed vertically onto the bottom of the contacter where it meets the treating agents rising through the holes 19. To produce a straight-line flow radial vanes 23 in the bottom of the contacter further prevent rotary movement of the liquid. The object of eliminating rotation of the liquid mixture is to cause it to flew at uniform velocity in cross-section and thus avoid low pressure slow iiowing eddies where separation of liquids and coalescence of treating agents occur.

The bottom of the contacter causes the mixed liquids to flow upwardly in the annu- The vanes supporting the tube further prevent any tendency toward rotation of the liquid in this annular space. The treating agents and oil- After passing throu-ghthe screen of liquids yflow tube and again passes downwardly as previously described. A portion of the mix- Y ture to an amountl comparableto that charged will'pass around. the baille 39 and be discharged from the top ofl the contactor through the outlet pipe 24.

This pipe 24 extends into the central part of the separator 25 where it divides into a header 26, the latter connected into a pipe 27 whose ends are closed and along the top of which are a plurality of'perforations 28. The pipe 27 is positioned in top of a hood 29, which is open at the bottom, as shown in Fig. 3.

In the top of the separator is a pipe'3() having 'closed ends, along the upper portion' of which is a narrow slit 'or a plurality of holes into which the oil .overflows passing thence to the line 30a and out throughv the discharge line 3l. Connected into the bottom of the separator is a header 32 into which the line 32 l is connected; this line is controlled by a valve 33 and a by-pass line 34,

automatically controlled by the liquid level device 35 in the line 32", which manipulates the valve 36 to maintain constant level of the heavier treating agents in the header 32. The float -in the liquid level control 35 is such that it will float uponthe heavier acid or soda solution, but will sink in the lighter distillate, thus the separated treating material is maintained at a level in the header 32, While the liquid distillate may till the separatorand overflow into the upper discharge line 30. The discharge apertures or slots through which the liquid is withdrawn to the line 30 are shown at 37 inA Fig. 3.

In operation the combined liquid treating material and oil pass lfrom the contactor through the line 24 and are`discharged from the top vents or holes in the line 27 beneath the hood 29. The mixture will flow downwardly until it reaches .the lower lips of the hood, shown in Fig. 3,y and during this slow downward flow the heavier treating material will separate by gravity, from the lighter distillate. Passing the lower lips of the liood the distillate rises to the discharge pipe 30. The flow in the separator, 'as shown in Fig. 3, by the arrows, is very slow so that the treatgravity than the distillate is separated out and gravitates to the lowerheader 32 while,

the distillate rises and overflows into the slot or narrow slotted apertures 37 inthe discharge pipe 30. The` primary object of Aintroducing Vthe mixture from the c'ontactor through a manifold and discharging it' w through a plurality of holes is to distribute it in a Vuniform, quantity per unit `settling area and to reduce its velocity of iow. The velocity of' low is continuously reduced .the numerals -in a stagnant pool.

until the liquidv rises tothe position of greatest cross-section of' the-liquid body in the settler. Y l' Furthermore the method of withdrawal -through orifices in a long pipe. is adaptedto maintain a low outiots7 velocity. The advantage of the low velocity How is to attain minimum disturbance to a separation of the age designated as tanks 2 and3 in Fig. 1.l

In the top of the settler and from the upper portion of the accelerating hood'29 are air Vent lines 38.

.In describing the mechanism shown in i Figs. 2, 3, 4 and 5, one single stage of contacting and separation has been explained, and the progress of the oil and treating material setout. It is understod, however, that the contacting and separation stagesl are separate stages which areintegnalportions of the system shown vin the flow "sheet A single contactinI stage bein designated by 1 C2 C3 ain` (34,` separating or settling stages in which the acid or sodaA are removed from the distillate are designated as S1 S2 S@ and S4. The novelty in the treatment lies particularly in the ra id circulation of a liq id through and aroun an open ended cylin er in'substantially vertical streams and injecting and dispersing through this moving stream a treating material. T he treatment' is limited in the 'period of contacting so that objectionable polymerization is reduced. Furthermore the contactor is made air tight topreveut oxidation and polymerization of the oil during the contacting period.

Heretofore a number of different methods have been employed to refine hydrocarbon distillates, among which are the common agitating tanks,.in which treating materials areadded and agitated with air; turbulent tube methodsin which the treating material and the hydrocarbon distillates are circulated through a plurality of tubes having friction return bent connections and finally settled Batlle' tubes and mechanical mixing devices have been used, as in thecentrifugal pumpmixing system, and separation by centrifuging. The disadvantages of the centrifugal pump mixin .method llies` primarily in the poor contro of the contact time and separation of the treating agent from the hydrocarbon distillate b'ecause of the centri'fugal'force in the mixing pump, also high investment and power cost are restrictive factors. Theuse of homogenizers is effective for combinin fthe distillate with the liquids, but 'the -capacity of tliiese devices are relatively limited power consumption high and distribution of treattreating thereof. Also considerably greater ing agents in homogenizer diiiicu'lt.

In the present treating system there is edected a highly eliicient mechanical means for accomplishing extremely intimate combi'- nation or dispersion of the hydrocarbon dis'- tillate with the treating agents' Within a period of time limited only by the speed ofr the chemical reaction or physical solution, the air being excluded and appreciable loss of hydrocarbon vapor prevented by the closed system. In this system acid is made to flow counter-current to the flow of the hydrocarbon distillate for ythe purpose of economyofacid and better treating of the distillate. The use of the counter-current acid flow in the systemreduces undesirable and wasteful polymerization of hydrocarbons and gives easy control of acid treating rate. Contact time is directly dependent upon the rate of change andthe volume of the contactor.

In normal operation the fresh acid is introduced to the third contacter or C3, being separated in -the third separator S3 and p-assing thence to C2 where it is again separated in S2 and finally being directed to the first contactor and after separation in S1 passing to spent acid storage. The distillate on the other hand passes successively from C1 to S1, thence to C2 and S2 and to C3 and S3 and nally into C4 and S4, the final stage of contacting and separation being with caustic soda, or similar alkali treatment. The fresh soda is charged to C4 or the fourth contactor and is separated in S4 passing thence to spent soda storage, While the finished distillate is discharged from Si through a line correspondingto the line designated as 31 in Fig. 2. -v

The treating liquids utilized arepreferably sulphuric acid, H2SO4, Caustic soda, or sodium plumbite, sodium or calsium hypochlorite, Water, H2O, or other acids vorv similar chemical agents, Wlichhave the ability of removing objectionable impurities from the hydrocarbon distillate.. The system is not limited to any treating agent, the novelty lying particularly 4 in the method of contacting and separation. In place of the separator shown a centrifuge or centrifugal separating means may be used in connection with the contacter.

To successfully separate the acid and partially spent acid from the oil in the successive separating steps presents diiculties not heretofore satisfactorily accomplished due to the close similarityof gravity of the partially spent acid sludge and oil. The present series of alternating contacting and separating stages utilizing' 'counteriow operation of the acid and oil has been successfully practiced commercially using lessacid pery barrel of oil treated and the operation materially decreased the loss of oil during the quantities of oil may be handled in this type of processing.

I claim as' my invention:

1. A closed method for treating petroleum oils, comprising the steps of subjecting the oil to a plurality of rapid contact treating steps with acid, alternating with steps of centrifugal separation, the acid being circulated in counterow relation to the oil so that the fresh acid initially contacts the oil in the final acid stage and progresses against the travel of' the oil after each step of separation, and is discharged from the initial acid treatin stage, said contact treating steps being limited substantially to the period of chemical reaction.

2. A method for treating petroleum oils comprising the steps of subjecting the oil to a plurality of rapid contact treating steps With acid, alternating with steps of centrifugal separation, the acid being circulated in counterflovv relation to the oil so that fresh acid contacts the oil in the final acid treating stage and progresses in an opposed direction to the travel of the oil after each step of separation, and is discharged from the initial acid treating stage, said acid treating steps preceded by a step of neutralization including contacting and separation step.

3. A method for treating petroleum oils comprising the steps of subjecting the oil to a plurality vof rapid contact treating steps with acid, said acid treating steps limited substantially to the time' period of chemical reaction alternating the acid treating steps With steps of centrifugal separation and passing the .acid in counterflow relation to the oil so that the fresh acid contacts the oil in the final acid treating stage and progresses in opposed direction to the travel of the oil after each step of separation, discharging the spent acid from the initial acid treating stage and subjecting the acid treated oil recovered from the final acid treating step to a step of neutralization including a contacting and separation step.

4. A methody for treating petroleum oils comprising the steps of subjecting the oil to a plurality of rapid contact treating steps gal separation, the acid being circulated in counterow relation to the oil so that fresh and separation step.

5. A method for treatin petroleum oils comprising the steps ofY su jectin the oil to a plura ity of rapid contact treating steps -with acid, alternating with steps or centrifugal separation, the acid bein circulated in 4counterziow relation to the o so that fresh acid contacts the oil in the inal acid treating stage and progresses in an opposed direction to the travel of the oil after each step of separation, and is discharged from the initial acid treating stagez said acid treating steps receded by a caustlc soda treat and followed y a, treatment with sodium lumbite, Vthe caustic soda and sodium plum ite steps in'- cluding contacting and separation steps.

CHARLES WALCOTT STRATFORD. 

